Individualized Medication of Voriconazole: A Practice Guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society

Background: Voriconazole (VRZ) is a second-generation triazole antifungal agent with broad-spectrum activity. It is available in both intravenous and oral formulations, and is primarily indicated for treating invasive aspergillosis. The most commonly used dose for adults is 4 mg/kg or 200 mg twice daily. VRZ presents nonlinear pharmacokinetics in adults, whereas drug–drug interactions and cytochrome P450 2C19 (CYP2C19) polymorphism are of great concern for VRZ. Because the liquid chromatography method has been widely used for measuring VRZ blood concentration, and target VRZ blood concentration has been recommended in some guidelines regarding efficacy and safety, therapeutic drug monitoring is considered as a useful tool for VRZ-individualized medication. Also, the CYP2C19 genotype test is available for guiding relevant drugs use in some health care facilities. Our objective was to develop an evidence-based practice guideline for VRZ-individualized medication. Methods: We followed the latest guideline definition from the Institute of Medicine and referred to the World Health Organization handbook for guideline development. The guideline was initially registered in the International Practice Guidelines Registry Platform (IPGRP-2015CN001). The guideline is, in principle, targeted at all Chinese health care providers. The quality of evidence and strength of the recommendations were assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method. Results: Twenty-six recommendations were formulated regarding therapeutic drug monitoring, special groups of patients, drug safety, off-indication use, and drug–drug interactions. Of them, 12 were strong recommendations. Most quality of evidence was low, very low, or expert opinions. Conclusions: We developed an evidence-based practice guideline for VRZ-individualized medication, which provided comprehensive and practical recommendations for health care providers. The development of the guideline exposed several research gaps to improve VRZ use.